Conventional hydraulic cylinders of the type used for actuating earthworking implements normally seal the rod end of the cylinder by means of a plurality of static seals. The seals perform a dual function; namely, to prevent egress of hydraulic fluid from the cylinder's working chamber and to prevent ingress of contaminants into the cylinder. U.S Pat. Nos. 3,540,741 and 3,578,341, for example, exemplify such prior art sealing structures.